1. Technical Field
The present disclosure relates to an apparatus for testing semiconductor integrated circuit chips, and more particularly, to a voltage apparatus for monitoring voltages of a power supply unit in a semiconductor probe station.
2. Discussion of Related Art
Generally, semiconductor products are manufactured through a series of semiconductor manufacturing process. The series of semiconductor manufacturing process include producing a pure silicon wafer, forming a plurality of semiconductor chips on the pure silicon wafer, performing an electrical die sorting (EDS) process, packaging the semiconductor chips, and performing a final test of the packaged semiconductor chips. In the EDS process, each integrated circuit (die) on the wafer is tested to see if the die functions, and inoperative dies are identified and discarded. Therefore, the EDS process is known to reduce an assembly cost and improve die yield.
An EDS process system is disclosed in U.S. Pat. Nos. 6,118,290, 6,353,221 and 6,170,116. The EDS process system includes a probe station, a chuck, a probe card, a performance board, and a tester system. The tester system includes a tester head and a tester body. A wafer is placed on the chuck configured on the probe station. The probe card, the performance board, and the tester head are configured on an upper portion of the chuck. An integrated circuit (IC) chip test program operates on the tester head. The tester body is electrically connected with the tester head. The probe card includes probe needles contacting each chip formed on the wafer and is used to check electrical conditions of the chips.
FIG. 1 is a schematic view of a conventional EDS process system for testing semiconductor chips.
Referring to FIG. 1, the EDS process system includes a probe station 101, a probe card 103, a performance board 105, a tester head 107, and a tester body 109. The probe station 101 includes a power supply unit (not shown) in which twelve voltage check terminals are configured. The power supply unit further includes a separated common ground terminal (not shown) and a receptacle (not shown) capable of supplying a voltage to an exterior.
The twelve voltage check terminals generally include set voltages such as a logic voltage (+/−5V) for the power supply unit and a voltage (+/−15V) for an M/H unit (not shown) conveying the wafer. A motor hold voltage (+8V) is another set voltage used to hold a motor when a driving motor stops. A motor driving voltage (+/−12V), a solenoid driving voltage (+24V), a permanent magnet voltage (+/−28V), an inker voltage are also used as set voltages. A sign, for example, “+/−” means that an allowable error range is an upper and lower 10% of the set voltage. A sign, for example, “+” means that an allowable error range is an upper 10% of the set voltage.
Conventionally, a general digital voltage apparatus is used to measure voltages between each voltage check terminal and the common ground terminal. A measured voltage is respectively compared with a set voltage. If the measured voltage is out of the allowable error range, the measured voltage is adjusted to be identical to the set voltage. Then, a voltage of another voltage check terminal is measured.